1. Field of the Invention
This invention relates to non-rigid aerodynamic balloons and more particularly to non-rigid balloons which are tethered and are used for advertising applications.
2. Description of the Prior Art
Aerodynamic tethered balloons for use in advertising or scientific applications, for example, are generally known. Such balloons usually have tail fins to keep them oriented and stable in the wind. These tail fins are either rigid or inflatable. Rigid fins maintain their shape because of the presence of structural members of metal or wood which support the tail fin membrane which may be flat or of an airfoil shape. Rigid fins are generally considered to have an advantage in some sizes of tethered balloons because they can be designed to be stiffer and to result in less stability problems. Their main disadvantage is that they are usually heavier, causing a payload penalty in medium size balloons, and being altogether too heavy to be practical on small, tethered balloons.
Inflatable fins are often desirable because of their lightness and because they can be readily made in airfoil shapes. A disadvantage of previous inflated tail fins has been the excessive amount of hand labor required to build and attach them, and the resulting large amount of seam area at the interface of the fin and the hull or main body of the balloon. This seam area has been notorious for leakage problems.